The biggest matchup of Week 14 pits the Houston Texans against the New England Patriots, who will appropriately have the nation's attention on "Monday Night Football" as they jockey for playoff positioning. The two teams will be battling for the No. 1 seed in the AFC as well as a potential first-round bye.

The Texans come in at 11-1 and have been in the discussion as one of the league's top teams since early in the season. They appeared to have the requisite balance on offense, as well as a similarly versatile defense that was capable of shutting down the best running and passing games in the league.

But in recent weeks, Houston has taken a step back, as the Texans' defense has shown weaknesses that have analysts concerned about their Super Bowl aspirations.

What has happened since early in the season, when the Texans appeared to have a championship defense?

Banged up in the secondary

A lot of Houston's struggles can be traced back to top cornerback Johnathan Joseph's battles with groin and hamstring injuries throughout much of the season. Houston's best corner, he generally draws the assignment of covering the opposing team's top wide receiver. Joseph's groin issues forced him into a midseason slump during which he graded at minus-8.0 over a three-game stretch.

Though he did bounce back to return to form, the hamstring has now kept him out since Week 11. His absence pushed CB Alan Ball into action against the Detroit Lions on Thanksgiving, when Ball surrendered 143 yards on the day (103 of which came in a mismatch against WR Calvin Johnson). Ball was also sidelined by injury last week, and he's unlikely to play on Monday night.

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